I'm thinking it is stretch marks from FL resizing? Can I trim, reload & fire form?

Looks like oil dents to me. Go easier on the lube and yes they should iron out with fireing

Yup, too much lube.

Here's one for you...I use Imperial wax lube, very sparingly and use a patch over a cotton mop to keep the die clean and I sometimes get "oil dents"...I keep wondering it it might be something like air getting compressed or trapped as the case gets to the final few thousands of an inch...long shot I know, but I've gotten dents on shoulders on fitted dies when I only waxed the lowest part of the case and that part was being sized maybe 0.001" at the max and the shoulder pushed back maybe 0.002".

Never seemed to cause any problems with accruacy tho'...just haven't found a good explaination yet.

It looks evenly distributed around the neck...might just be the brass collapsing due to stress/weakness/reshaping.

Fireform one and see how it comes out.

Luck

Thanks all, wonder if it more prevalent on some calibers; never had it until I started loading 300 H&H.

quote:

Originally posted by FOOBAR:
Here's one for you...I use Imperial wax lube, very sparingly and use a patch over a cotton mop to keep the die clean and I sometimes get "oil dents"...I keep wondering it it might be something like air getting compressed or trapped as the case gets to the final few thousands of an inch...long shot I know,

If it looked anything like the photo you're talking one hell of a lot of compressed air. Only times I've had this is when I got sloppy with uncompressible ( wax, oil, grease ) lubes . roger

As others have stated it is probably too much lube. As long as the round chambers the dents should fire form out with no problems.
Occasionally you will get a wrinkle in the brass where a dent is, after firing, but not often.

I have heard of some who drill a pin hole througn at the base of the neck of the fls die to release any air pressure but have not done so myself. That definately looks like lube dents though. I usually only lube about 2/3 the length of the case because it is the base of the case that can cause the stuck in die syndrone. The top part of the case walls and above is (in proportion) quite thin and malleable and rarely causes a sticking problem with the lube hydraulicing a minute amount of lube forward toward the shoulder to take care of that end of the case, and as the shoulder-neck is not lubed this is not the part of the case that can cause a sticking problem.

Von Gruff.

Abob

Is your die clean? Make sure the built-in relief point thingy isn't gunked up...

I have a set of Redding dies that will do to if I try to run the case in to quickly. That is for a 300 Extreme.

If it happens after FL sizing, its to much lube. If it happens after firing, the powder is to slow burn rate & charge is to light. The neck is not sealing the chamber. Gas pressure is crushing the brass from the outside.

I did say I cleaned my die and used tiny amounts of Imperial wax...I haven't had a die with a relief hole in it for a long time.

I've had more of his phenomonon with reforming sharp angled shoulder case...284 to 6mm etc...even had a few 6.5mm-284 Hornady forming to 6mm-284.

I can't explain it...I quit using anything but Imperial wax for forming and sizing well over 30 years ago and I've done a bunch of various wildcats and/or case reforming since the mid 50's. I get a collapsed case now and then going to fast or not fast enough on the ram stroke and dents now and then, but everytime I look for the cause it's one of those could be this, could be that...doesn't matter to me by now...as long as the dent doesn't fold over or crack down the middle at the first firing, the case seems to last as long as any other.

This picture is the first case I've seen with such uniform dents all around the case...usually I've seen/made only one dent.

I reformed 50 Hornady 6.5-284 cases 3 weeks ago and cleaned the die every 3-4 sizings, just a trace of wax on the neck and base and still got a few with shoulder dents with no discernible pattern as to when it happened.

Your right Bartsche, I just guessed at air compression, grabbing at straws so to speak, I couldn't get past the physics aspects having spent a lot of time working with air and hydraulic systems in heavy vehicls...kinda embarrasing to even propose it, but if you look at the pressures involved over the small areas...maybe...

Von Gruff...you pointed out some of the other snags...so maybe the total information will help Jim.

Luck

It is just too much lube being used.
Keep lube off of the shoulder.

thanks to all, this is why I love AR

I went over it in my head, I know better than to over-lube; I also switched to Imperial wax (also like their neck lube application material)

However, I was re-sizing before using my new Belted Magnum Collet Resizing Die from Larry Willis for the 1st time; in the instructions Larry states: "Use plenty of "Imperial Sizing Die Wax" for best results." I'm thinking I sub-conscientiously applied these instructions to my FL resizing; plus last couple of years I have primarily been using Lee's collet neck dies so it has been a while since I lubed a case

Take 2! I have had shoulder folding before but not to the extent or uniformity as seen in the photos. Mostly it occurred in long shoulders with shallow angles and trying to move to much metal at one time. Use of several bushings followed by a FL sizing die corrected this problem.The most resent was my 22 Jet rimless wildcat. roger

Just duplicated the photo while loading some 6.5.R-bar cases. One case was not completely formed by a good bit. Instead of getting out any bushings I tried to move the whole shoulder down with the die . It really was serendepitous but there you have it. It was not lube. If someone wants to post the photo for me I'll E-Mail it to them. roger